When you drink, ADH production is decreased, which causes more urine production. Once you've urinated the first time, and continue drinking, the bladder feels the need to be emptied more often.
"Breaking the Seal" or having to urinate more once you do for the first time is purely a psychological effect. Interestingly though, alcohol DOES cause your body to produce more urine because it inhibits the release of the hormone ADH from your pituitary gland which in turn causes your body to produce a higher volume of dilute urine.
Breaking the seal is simply going to the bathroom for the first time after you have been drinking for awhile. Usually there will be a lot more trips if you continue!
